Field
The present disclosure relates generally to communication systems, and more particularly, to evolved packet data gateway (ePDG) selection.
Background
A user equipment (UE) that needs wireless access in order to support communications services (e.g. such as making an emergency call) on behalf of the user of the UE and/or applications on the UE may sometimes need to access a wireless local area network (WLAN), such as defined by the IEEE 802.11x standards. This may occur when wireless cellular access is not available at the UE's location or when wireless cellular coverage is available but is not preferred (such as caused by high cellular access charges if a UE is roaming). In that case, if there is an available WLAN access point (AP) within radio range of the UE that is not considered as trusted by the UE (e.g. not belonging to a cellular network operator), the UE may need to establish communication services (e.g. establish an emergency call) by accessing a cellular network by means of the WLAN AP through a gateway entity in the cellular network known as an evolved packet data gateway (ePDG). The ePDG may provide access for the UE to other entities in the cellular network such as a packet data network (PDN) gateway and an Internet Protocol (IP) Multimedia Subsystem (IMS) through which communication services (e.g. establishing an emergency call or a non-emergency call) may be supported. Selection of a suitable ePDG by the UE and, by association, selection of the cellular network that owns the ePDG, may then be a critical part of establishing communication services, such as establishing an emergency call.